Messages in this thread | | | Subject | Re: [PATCH] drm/radeon: Convert get_user_pages() --> pin_user_pages() | From | John Hubbard <> | Date | Tue, 26 May 2020 15:57:45 -0700 |
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On 2020-05-26 14:00, Souptick Joarder wrote: > This code was using get_user_pages(), in a "Case 2" scenario > (DMA/RDMA), using the categorization from [1]. That means that it's > time to convert the get_user_pages() + release_pages() calls to > pin_user_pages() + unpin_user_pages() calls. > > There is some helpful background in [2]: basically, this is a small > part of fixing a long-standing disconnect between pinning pages, and > file systems' use of those pages. > > [1] Documentation/core-api/pin_user_pages.rst > > [2] "Explicit pinning of user-space pages": > https://lwn.net/Articles/807108/ > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > Cc: John Hubbard <jhubbard@nvidia.com> > > Hi, > > I'm compile tested this, but unable to run-time test, so any testing > help is much appriciated. > --- > drivers/gpu/drm/radeon/radeon_ttm.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c > index 5d50c9e..e927de2 100644 > --- a/drivers/gpu/drm/radeon/radeon_ttm.c > +++ b/drivers/gpu/drm/radeon/radeon_ttm.c > @@ -506,7 +506,7 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm) > uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE; > struct page **pages = ttm->pages + pinned; > > - r = get_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0, > + r = pin_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0, > pages, NULL); > if (r < 0) > goto release_pages; > @@ -535,7 +535,7 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm) > kfree(ttm->sg); > > release_pages: > - release_pages(ttm->pages, pinned); > + unpin_user_pages(ttm->pages, pinned); > return r; > } > > @@ -562,7 +562,7 @@ static void radeon_ttm_tt_unpin_userptr(struct ttm_tt *ttm) > set_page_dirty(page);
Maybe we also need a preceding patch, to fix the above? It should be set_page_dirty_lock(), rather than set_page_dirty(), unless I'm overlooking something (which is very possible!).
Either way, from a tunnel vision perspective of changing gup to pup, this looks good to me, so
Acked-by: John Hubbard <jhubbard@nvidia.com>
thanks, -- John Hubbard NVIDIA
> > mark_page_accessed(page); > - put_page(page); > + unpin_user_page(page); > } > > sg_free_table(ttm->sg); >
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